Understanding Power Take-Off
Power Take-Offs, or PTOs, are mechanical gearboxes that attach to mounting faces provided on truck transmissions. They are used to transmit power from the trucks engine to other auxiliary components. There is a variety of auxiliary components powered by power take-off but one of the most common is a hydraulic pump. The PTO provides power to the hydraulic pump generating hydraulic flow and pressure which can be directed to hydraulic cylinders or hydraulic motors to perform work.
The image above shows a PTO and direct mount hydraulic pump mounted to a transmission.
Some transmissions have multiple PTO openings as seen here.
PTOs can also come equipped with an output shaft the is coupled directly to the input shafts in applications such as generators, air compressors, pneumatic blowers, vacuum pumps and liquid transfer pumps. The typical installation here would involve the PTO and a drive shaft or drive line.